Research progress in optimization of therapeutic effect of antibodies against flavivirus / 中华微生物学和免疫学杂志

Flaviviruses are a class of positive-strand RNA viruses mainly transmitted by arthropods, which can cause high mortality and morbidity worldwide. At present, there is no specific therapy. Therapeutic antibodies bring hope for the treatment of flavivirus infection, but the antibody-dependent enhancement (ADE) effect induced by flavivirus infection can lead to disease progression. The ideal therapeutic antibodies against flaviviruses should not only treat flavivirus infection, but also avoid the harm caused by ADE. Therefore, researchers have optimized some of the antibodies to seek the best therapeutic antibodies. This review briefly described the research progress and mechanism of therapeutic antibodies against flaviviruses as well as some strategies to reduce the ADE effect induced by the therapeutic antibodies.

Establishment of an in vivo neutralization model based on H5N1 pseudovirus / 中华微生物学和免疫学杂志

Objective:To establish an in vivo infection model of H5N1 pseudovirus and to detect the neutralizing activity of FHA3 antibody using this model. Methods:Based on the sequence information of hemagglutinin (HA) and neuraminidase (NA) of A/Anhui/1/2005/H5N1 strain, two recombinant plasmids of pcDNA3.1-HA5 and pcDNA3.1-NA1 were constructed. The two plasmids and plasmid pNL4-3.Luc.R-E- were co-transfected into 293T cells to prepare H5N1 pseudovirus supernatant. The morphology of pseudovirus particles in the supernatant was observed by electron microscopy. MDCK cells were infected with the pseudovirus supernatant and the virus titer was detected. BALB/c mice were injected with the pseudovirus supernatant by intraperitoneal injection and subjected to bioluminescence imaging at 2, 5, 8, and 12 d after infection to detect the pseudovirus infection in vivo. The functional activity of FHA3 antibody in vivo was evaluated using the established mouse infection model. Results:The recombinant plasmids pcDNA3.1-HA5 and pcDNA3.1-NA1 were correctly constructed and could be used to prepare pseudovirus supernatants of high titer by co-transfecting 293T cells with the plasmid pNL4-3.Luc.R-E-. The virus particles were round under electron microscope. H5N1 pseudovirus-infected mice exhibits strong fluorescence signals, which were attenuated by FHA3 treatment before challenge.Conclusions:The in vivo infection model of H5N1 pseudovirus was successfully constructed and FHA3 antibody was proved to be protective against the pseudovirus infection.